Democratic congressional challenger Nancy Boyda repeated concerns Wednesday about a proposed multilane superhighway that eventually could span the United States from Mexico to Canada, calling it a threat to Kansans.

"There seems to be a plan to blur the border with the United States and Mexico," Boyda said, referring to a proposed 10-lane corridor parallel to Interstate 35 in Texas.

Boyda has made the highway an issue in her effort to defeat incumbent Republican Jim Ryun in a rematch of their 2nd District race two years ago. While Ryun says immigration is the top issue on his agenda, Boyda said allowing Texas to "blow a quarter-mile-wide hole in the border" runs afoul with any get-tough talk.

Speaking Wednesday at a candidate forum in Topeka, Ryun dismissed the Texas proposal and fears of a flow of illegal guns, drugs and immigrants as nothing more than a growing conspiracy theory.

"This is definitely based on fiction," Ryun said. "It is based on an Internet story."

State and regional highway officials agree, saying there are no grandiose plans to cut a wide swath across the central United States from Laredo, Texas, to Detroit.

Terry Heidner, Kansas Department of Transportation director of planning and development, said any potential for expanding Interstate 35 through Kansas is in the distant future...